The principal applicant coordinates the physical health and disability module of the English Longitudinal Study of Ageing. Dr Melzer's longer-term research program addresses two key public health questions in aging: 'how much of future disability in older people is avoidable?' and 'how best could population prevention and early detection efforts be targeted in older populations?' [unreadable] [unreadable] This project proposes epidemiological analyses of disability data from two NIA supported nationally representative public datasets: the English Longitudinal Study of Ageing (ELSA) and its sister study, the US Health and Retirement Survey (HRS). The proposed work aims to test the comparability of disability self-reporting across these studies, and establish whether associations between risk factors and disabilities are consistent across the two studies/countries. [unreadable] [unreadable] This international comparison will extend our understanding of risk factors for disability, by studying more diverse risk exposures, and the effects of differing social, economic, and healthcare environments. The results will provide a foundation for a range of multidisciplinary analyses involving disability, and a baseline for tracking trends in disability in ELSA and HRS. Many identical or comparable questions have been included in ELSA from HRS. In addition, gait speed measures in the ELSA study will be used to provide an objective 'calibration' of self-reporting of functional mobility status to the US population, using the NHANESIII dataset. [unreadable] [unreadable] In addressing the validity problems in international comparisons, and in covering unusually large nationally representative samples, this work represents an exciting step forward in the field of international health and disability research in aging populations. [unreadable] [unreadable]